BA.5, sometimes known as the “sibling” of the Omicron variant has become a dominant form of the virus in recent weeks.
In the US, BA.5 currently accounts for around 65 percent of Covid cases, according to the CDC, and it is also dominating infections in the UK.
And it is not just the same as all the other Covid variants, in terms of its symptoms.
“One extra symptom from BA.5 I saw this morning is night sweats," Professor Luke O’Neill, a Professor of biochemistry from Trinity College Dublin, told Irish radio station NewsTalk .
“Isn’t that strange?" he added.
He added the different symptoms were partially due to genetic changes to the virus and the way our immune system reacts to an infection.
“The disease is slightly different because the virus has changed. There is some immunity to it – obviously with the T-cells and so on,” O’Neill added. “And that mix of your immune system and the virus being slightly different might give rise to a slightly different disease – with strangely enough – night sweats being a feature."
Evidence suggests the BA.5 subvariant may be similar to Omicron in that it causes less severe disease and death than previous variants, like Delta, but its ability to reinfect is a cause for concern.
According to the ZOE Covid Study app, the most reported Covid symptoms among vaccinated people (two doses) include: runny nose, headache, sneezing, sore throat, and persistent cough.